Work clamping device for machine tools



April 21, 1942.

INVENTOR I QZZ'MSIRIFORZZ '1 V [I] I X A rra/wver The particular embodiment of Patented Apr. 21, i942 UNITED, STATES PATENT OFFICE our F. Mastriforte, West Hartford. com, assign-- e or to Niles-Bement-Pond Company, West Hartford, Conn., a corporation of New; Jersey Application October 23, 1940, Serial No. 362,430

4 Claims.

This invention relates to metal cutting machines and particularly to a machine in which a work piece being operated on is supported slidably in position upon a fixed axis and against rotation; and the tool, usually in the form of a drill, reamer or other. internal cutting tool, is passed from end to end of the work piece while being rapidly rotated.

More particularly the present invention relates to means for clamping a work piece upona fixed axis and against rotation for a cutting operation thereon, there being work clamping devices at each end of the work piece adapted to be opened and closed manually by a single mechanism which will cause the clamping devices to firmly grasp the work piece regardless of the particular diameter engaged by either clamping device.

A primary object of the present invention is to provide a convenient, efiicient, and rapid work supporting means particularly for elongated work scope of the invention, the claims appended to this specification being relied upon for that purpose. a

such as gun barrels, there being manual means I to simultaneously open and close the work clamping members which engage the extreme ends of the work piece.

One feature which enables me to accomplish the above object is that the manually operated means may simultaneously rotate the work.

clamping devices at opposite ends of the work piece, and, when one of the clamping members engages the work piece, the other clamping device maycontinue to close upon its end of the work and finally both clamping members will simultaneously rigidly clamp the work upon the axis of the clamping devices and against rotation. i

the invention described and illustrated in the present application is forreaming gun barrels, there being three complete units disposed obliquely one above the other and upon the same base of the machine shown in the drawing. As each unit is complete in itself, but one of them is thought to require specific description.

. In the drawing: V

Figure 1 is a-front elevation of a portion of a machine having the present form of work clamping means, sections of the base being broken away. r

Fig. 2 is an end elevation of some of the parts shown in Fig. 1, one of the work clamping members being shown in section.

' Fig. 3 is an end elevation of other parts shown 7 in Fig. 1, one of the clamp actuating members being shown in section.

Fig. 4 is a detail sectional view showing the mounting for one of the work clamp operating worms.

Fig. 5 is a front elevation, partly in section, showing the support and guide for the cutting tool, and

Fig. 6 is a front elevation, partly in section, of

the manually rotatable member to simultaneously open and close the work clamping members.

In the above-mentioned drawing there has been shown but one embodiment of the invention which is now deemed preferable, but it is to be understood that changes and modifications may be made within the scope of the appended claims :vithout departing from the spirit of the invenion.

Briefly and in its preferred aspect, the invention may include the following principal parts: first, work clamping devices, there being two, each mounted for engaaementof the work piece at or adjacent an endof the work piecef'second, oppositely movable jaws in each of the clamping memberssimultaneously movable to engage and disengage the work piece by means of a rotatable member having right and left hand screws within the body member of each work clamp; third, elongated worms mounted in each of the work 'clampingmembers and engaging the rotatable With the, above and other objects in view, the

be otherwise embodied and that the drawing is not to be construed, as defining or limiting the member for opening and closing the clamping jaws,', theworm being mounted for limited slid-j able movement in addition to its rotation; fourth,

a rotatable splined shaft connecting the worms for simultaneous rotation; and fifth, manual means to rotate the splined shaft to rotate or slidably move the two worms.

Referring more in detail to the figures of the drawing, to illustrate one embodiment of the invention I provide work clampingmechanism for a gun barrel reamer in which the gun barrel being operated on is supported slidably upon a fixed axis and retained against rotation by suitsuitable rotatable cutting tools ll.

able clamping members or chucks. As shown in Figs. 1 and 2, the clamping devices I. are disposed for engagement of the work piece W adjacent its opposite ends and between these two clamping members II is a manually operating means II for opening and closing the jaws l2 engaging the work piece W. In machines of the above type, it is essential that each clamping member ll firmly engage the work piece W regardless of difierences in diameter at its opposite ends. It is also desirable to have a single rapidly and conveniently operated means for simultaneously clamping the Jaws I! of the two members ll upon the opposite ends of the work W so that work pieces may be quickly removed and others inserted in their place.

The machine illustrated in the drawing has three work supporting units and three tool operating units. Each of these is similar to the others and for that reason but one will require description. As shown in Figs. 1, 2 and 3, the three units are supported one above the other upon suitable. brackets ll on a carriage slidable upon the bed ll of a suitable machine tool.

At the left of the machine as seen in Fig. l is a headstock I 8 having three tool spindles l6 extending therefrom in which may be mounted Means are also provided to individually mount these three cutting tools I'l rotatably in their headstock l and axially of the work pieces W being operated on. Slidable movement of the carriage and bracket II with the work pieces W engages the cutters with the entire length of the work pieces. As these cutting tools II form no part of the present invention, it is not thought necessary that their construction or operation be described.

Referring particularly to Figs. 1, 2 and 3, it will be seen that there are work clamping members III, more clearly shown in Fig. 2, keyed or otherwise secured in position upon the supporting bracket I3. In the body portion of these work clamping members or chucks iii are mounted opposed jaws l2 movable radially to engage or disengage the work piece W. Also in the body portion" is a right and left hand threaded member it having a central gear thereon by means of which the Jaws I! may be simultaneously moved to'clamping or unclamping position. It will be understood that the clamping members ill at the opposite ends of the work are duplicates of each other. It is the particular purpose of the invention to permit simultaneous clamping action of the two work clamps or chucks III regardless of differences in diameter of the opposite ends of the work elongated splined shaft l9. Its' opposite ends are provided with worms 20 as shown more particularly in Fig. 4, retained against sliding movement upon the splined shaft i8 by means of clamping collars II at opposite ends. It will be seen from an inspection of Fig. 4 that the worm III is substantially longer than the bushing slide axially with the splined shaft a limited distance untilone of the clamping collars 2! engages against the end face of the bushing 22.

In order to rotate this splined shaft I 9 to force rotation of the two worms 20 and axial sliding movement of the worms and splined shaft to compensate for differences in diameter of the work W engaged by the two clamping members II. a unitary operating mechanism Ii is provided. This operating device I I is more clearly shown in Figs. 3 and 6, in whichit will be seen that the splined shaft l9 passes centrally through a rotatable member 23 supported preferably upon anti-friction bearings 28 within a portion of its body member ll'and having gear teeth 28 at its central portion. Engaging the gear teeth. 2! of this member 23 is a gear 24 upon the rear end of a forwardly extending shaft 25, there being a handle 26 upon the outer or free end of this shaft. The actuating members II are, as shown in Figs. 1 and 3, mounted in the central portion of bracket i3 secured to the base it. A separate actuating means II is provided for each unit so that rotation of a handle 26 opens or closes one pair of chucks l0 engaging the opposite ends of a work piece W.

In operation and with the clamping members It of a ,unit open, a work piece W is inserted in position and the handle 26 of the operating member rotated for that unit. This rotates the splined shaft l9 through the gear connections described above and thus rotates the worms 2' engaging with the jaw closing members i8. Rotation of these members it will continue until one or the other firmly clamps its end of the work piece W. Continued rotation of the splined shaft i9 will then cause sliding movement of the worm 20 instead of rotation of the large closing members and this will continue until the clamp at the opposite endof the work piece firmly engages itsend, whereupon both clamps will firmly and equally engage the work piece regardless of which member is clamping upon a larger or smaller diameter. But one of the worms 20 is shown which is of right hand helix. It will be understood, however, that the worm 20 for the work clamp at the opposite end of the work piece W must be of the opposite or left hand helix.

To guide the tool H as it enters the work piece W a housing 30 may be provided as shown in Fig. 5. This member, however, forms no part of the present invention.

What I claim is:

1. Work holding means for machine tools comprising in combination, a pair of axially spaced chucks positioned to engage spaced portions of an 22 within which it is mounted so that it may elongated work piece having different diameters at its chuck engaging points, jaws movable within said chucks, a member within each chuck engaging the jaws thereof, each of said members having a gear formed centrally thereof, worms engaging said gears and mounted for limited independent axial movement, and unitary manual means to simultaneously rotate said worms.

2. Work holding means for machine tools comprising in combination, a pair of axially spaced chucks positioned to engage spaced portions of an elongated work piece having different diameters at its chuck engaging points, jaws movable radially within said chucks, a rightand lefthand screw threaded member within each chuck engaging the jaws thereof, each of said members having a gear formed centrally thereof, worms engaging said gears and mounted for limited independent axial movement, and unitary manual means slidably engaging said worms to simultaneously rotate said worms.

3. Work holding means for machine tools comprising in combination, a pair of axially spaced chucks positioned to engage spaced portions of anelongated work piece having, different diameters at its chuck engaging points, jaws movable radially within said chucks, a member within each chuck engaging the jaws thereof rotation of which simultaneously operates said jaws, said members having a gear formed centrally thereof, worms engaging I said gears and mounted for limited independent axial movement, and unitary manual means to simultaneously rotate said worms.

' position.

4. Work holding means for machine tools comprising in combination, a pair of axially spaced chucks positioned to engage spaced portions of an elongated work piece having different diameters at its chuck engaging points, jaws movable radially within said chucks, a member within each chuck engagingthe jaws thereof, said members having a gear formed centrally thereof, worms engaging saidgears and mounted for limited independent axial movement, and unitary manual means to simultaneously rotate said worms, said rotating means having adjustably mounted collars thereon to retain said worms in axial OTIL F. MASTRIFQRTE. 

